Asymmetric catalytic reactions are important in organic chemistry. In past thirty years, the asymmetric catalytic reaction is catalyzed by an organic chelating agent coupled to a metal center. However, the usage of metals results in environmental pollutions. Therefore, as the increased requirement of quality of pharmaceutical production, the catalyst using pure organic molecules other than the catalyst system having metals is a better and wiser choice in the industry.
In pharmaceutical chemistry, many organic intermediates depend on organocatalysts which are used for asymmetric catalytic reactions. Although some research has reported that asymmetric Michael addition reactions can be performed in water or saline solution, the solvents used in the reactions have influences in environment, and moreover, for certain compounds having no reaction in aqueous solution, the synthesis of pharmaceutical compound would be more difficult and complicated. In addition, the target yield is obtained by using even more than 50 mol % of the conventional organocatalysts.
Accordingly, it is an urgent issue to develop an organocatalyst with less amount for enhancing yield and enantioselectivity in a relatively mild condition, such as low toxicity, metals-free, aqueous solution or even solvent-free system.